ios - Parse.com 框架排序日期下一个生日

Question

需要使用 Parse.com 在 iOS 上按日期排序，但我需要根据特定人的下一个生日来排序。我尝试在当前或明年添加日期和月份，这很有帮助，但这将是一个手动过程，任何以自动方式执行此操作的建议。

作为旁注，我想快速实现它

提前致谢。

Answer 1

确切的代码将取决于您的个人设置(我可以想象您已经创建了 PFObject 或类似的子类)，但请尝试使用以下代码进行试验。我还制作了另一个名为 filterFriendsAfterBirthdays 的函数，它可能对阅读本文的人有用。

//
//  ViewController.swift
//  ParseFun
//
//  Created by Stefan Veis Pennerup on 20/06/15.
//  Copyright (c) 2015 Kumuluzz. All rights reserved.
//

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        createDummyData()
        queryForFriends() {
            println("Unsorted birthdays: \($0)")
            println("Sorted birthdays: \(self.filterFriendsAfterBirthdays($0))")
            println("Closets upcoming birthday: \(self.filterFriendsBasedOnClosetsUpcomingBirthday($0))")
        }
    }

    func createDummyData() {
        for var i = 0; i < 25; i++ {
            let myFriend = PFObject(className: "Friends")
            let interval = Double(arc4random_uniform(UInt32.max))
            myFriend["birthday"] = NSDate(timeIntervalSince1970: interval)
            myFriend.saveInBackground()
        }
    }

    func queryForFriends(completionHandler: ([PFObject]) -> ()) {
        let friendsQuery = PFQuery(className: "Friends")
        friendsQuery.findObjectsInBackgroundWithBlock { (result, error) in
            if (error != nil) { return }
            let pfArray = result as! [PFObject]
            completionHandler(pfArray)
        }
    }

    func filterFriendsAfterBirthdays(friends: [PFObject]) -> [PFObject] {
        return friends.sorted {
            return ($0["birthday"] as! NSDate).compare($1["birthday"] as! NSDate) == .OrderedAscending
        }
    }

    func filterFriendsBasedOnClosetsUpcomingBirthday(friends: [PFObject]) -> [PFObject] {
        let cal = NSCalendar.currentCalendar()

        // Specifies the day unit
        let dayUnit: NSCalendarUnit = .CalendarUnitDay

        // Gets todays year
        let today = NSDate()
        let yearUnit: NSCalendarUnit = .CalendarUnitYear
        let yearToday = cal.components(yearUnit, fromDate: today)

        // Combined days and year units
        let combinedUnits: NSCalendarUnit = .CalendarUnitYear | .CalendarUnitDay

        return friends.sorted {
            // Gets the birthday components since today
            // Also uses the year unit to ensure that the day will be between -365 and 365
            let birth1Components = cal.components(combinedUnits, fromDate: today, toDate: ($0["birthday"] as! NSDate), options: nil)
            let birth2Components = cal.components(combinedUnits, fromDate: today, toDate: ($1["birthday"] as! NSDate), options: nil)

            // Updates the days to a positive integer
            if (birth1Components.day < 0) { birth1Components.day += 365 }
            if (birth2Components.day < 0) { birth2Components.day += 365 }

            return birth1Components.day <= birth2Components.day
        }
    }
}